Short posts are bad at crossing inferential distances. They limit your readers to those who already know, or almost know, what you're talking about. (Also see: Explainers Shoot High. Aim Low!)
For example, if you were writing a scientific paper and going for extreme terseness you would give the data then stop. There'd be no abstract, no explanation of previous work and surrounding context, and no guiding towards conclusions. It would be an incredibly inefficient way to convey knowledge.
Another example is computer programs. Programmers try to avoid repeating themselves, but not to the point where they attempt to hit the Kolmogorov complexity (code so unreadable it's unprovably correct!) or omit all tests (which are by definition redundant).
A more personal example is a post I made recently: Building your own Quantum Fourier Transform. I did not explain how to use the little quantum circuit inspector in enough detail, and so all the feedback was "I don't get it". I try to always keep in mind that saying things like "a superposition assigns a weighting to all the classical states" just doesn't translate, you have to break it down every time, but I didn't pay attention to that nagging doubt.
Unfortunately, long posts are also bad at crossing inferential distances. One reason is that if a post is long people will have forgotten the first half of the post by the time they reach the end. And the longer a post gets the more likely it is people will focus on a small detail instead of the bigger picture. Not to mention that it's more difficult and time-consuming to write long posts, so quality will suffer.
Bite-sized posts that have only one thing people should take away from it are much less likely to be misunderstood. And they can still can still t...
I like posts that are concise and to the point. Posts like that maximize my information/effort ratio. I would really like to see experienced rationalists simply post a list of things they believe on any given subject with a short explanation for why they believe each of those things. Then I could go ahead and adjust my beliefs based on those lists as necessary.
Sadly I don’t see any posts like this. Presumably this is because of the social convention where you’re expected to back up any public belief with arguments, so that other people can attempt to poke holes in them. I find this strange because the arguments people present rarely have anything to do with why they believe those things, which makes the whole exercise a giant distraction from the main point that the author is trying to bring across. In order to prevent this kind of derailment, posters tend to cover their arguments with endless qualifications so that their sentences read like this: “I personally believe that, in cases X Y Z and under circumstances B and C, ceteris paribus and barring obvious exceptions, it seems safe to say that murder is wrong, though of course I could be mistaken.” The problems with such excessive argumentation and qualification are threefold:
By contrast, terseness makes posts more readable and makes it less likely that the main point is misunderstood. So if we as a community could just relax the demand for argumentation and qualification somewhat, and we all focussed on debating the main points of posts instead of getting sidetracked, then perhaps experienced rationalists here could write nice and concise posts that give clear and direct answers to complicated questions. Instead, some of the sequences are so long and involve so many arguments, counter-arguments and disclaimers that I feel the point is lost entirely.